Ants (Lasius niger)

How do I get rid of ants in my home?

The first step is to Kill off the Ant Queen. And by doing so will rid their source.   The Queen produces  a large number of ants and killing it will exterminate them. You can find the queen inside the ant nest, and believe it or not it's rather shy and will hide in the bottom of the nest.

Secondly you must remove the food source. The reason ants are coming into your humble abode is because it's a free-for-all (or at least it was at some point in the past, and they're hoping it might be again). The cleaner you keep the house, the less they'll have to eat, and the more they'll look elsewhere for goodies.

  • Wipe down all surfaces. Tables and counter tops should be regularly sprayed and cleaned with a mild bleach or vinegar solution. Make sure you keep on top of (or even step up) your regular cleaning regimen; sweep, mop, and vacuum regularly.
  • Put food in air-tight containers. This, of course, has the added bonus of keeping the food fresher.
  • Keep the sink clean: no dirty dishes, no standing water for ants to drink, and no food in the drain.
  • Put pet food bowls in a slightly larger bowl and add some water to the larger bowl, creating a moat around the pet food that the ants can't easily cross (if only you could do the same around your house!).


Black garden ant with a spider's Chelicerae. The black garden ant (Lasius niger) is a formicine ant, which is the type species of the Subgenus Lasius, which are  found all over Europe and in some parts of North America and Asia. It is monogynous, meaning colonies have a single queen.

Thirdly kill any “scouts”.  Colonies regularly send out lone ants to check for food sources. If you see an individual ant strolling across your coffee table, don't let it make it back to the nest alive. It'll tell the colony where you spilled the apple juice. If the scout made it back to the nest and brought back some friends, they'll be following a scent trail, single file. Unless you're ready to bait them as described below, kill them all, and Quickly so!

  • Spray the trail with all-purpose cleaner or a bleach solution, then wipe it up with a wet paper towel. Spraying the nest can be effective, but you really want to make sure you get them all, otherwise killing part of the colony can simply encourage certain species to establish new colonies, which is counter-productive to you.[1].
  • For a less hands-on solution, vacuum them all up, then vacuum some talcum powder or diatomaceous earth to finish them off. This second step is important to make sure that you don't provide the ants a new home inside your vacuum cleaner.
  • “Ant proof” your home. Since ants are tiny, they can find thousands of tiny doorways into your residence. Some of them of are easy to identify; others will only be discovered when there's a parade of ants marching through them.
  • Seal windows, doors, and any cracks the ants crawl through with caulk. An additional benefit with this is better temperature control and lower energy bills. Plus, it's one of the least risky methods when kids or pets are involved. Line suspected entryways with deterrent substances.

Diatomaceous earth is a fine powder that kills ants by pulling all the moisture from their bodies. Since it works by absorbing moisture from the ant itself, however, it's best used in dry environments. You also don't want anyone in the house (pets included) sniffing it up. Salt works just fine as well, and you can spread it under doors, near windows and walls with better conscience. Talc in various forms is thought to deter ants, although the mechanism is poorly understood. Tailor's chalk and baby powder usually contain talc and can be used to create a barrier for ants. Regardless of which form of talc you use, keep in mind that there are concerns about the potential carcinogenicity of talc, although baby powder is used by many parents nonetheless.

  • Many sources recommend using normal chalk, but this is made of gypsum, not talc, and this misconception could be the result of confusion with "ant chalk" (an insecticide that looks just like normal chalk; outlawed in the US in the '90s, but still sold in Chinatowns illegally).
  • Some baby powder brands are made of corn starch and will not work effectively against ants. Check the ingredients. Cornmeal can be used as a weapon against ants, and it's not poisonous to people or animals. Ants eat it, and after consuming water, the cornmeal swells inside their digestive organs, killing the ants.  Also try dried cloves, scents and substances that ants simply don't like for various reasons.  Other substances are  vinegar, peppermint oil, cinnamon, black pepper, cayenne pepper, whole cloves, and bay leaves. Some of these might be harmful to pets and irritants to curious children.  Excavated the  ants' nest and remove it. If ants continue to raid your home, you're going to have to raid theirs. If you're able to locate the nest, you can pour several gallons of boiling water into it and that'll be that. But if you don't know where they're coming from, your other alternative is to bait them.


Commercial bait product do also work.  Just pick your poison. Mixing boric acid powder or Borax with maple syrup is the most common bait (and it is what the popular commercial ant poison, Terro, basically consists of). Boric acid affects ants both externally (when in powder form; similar to diatomaceous earth) and internally (when ingested). The ants bring the poison (Borax or boric acid) with them to the colony and spread it around. If you get the quantity and timing just right, you can wipe out a large colony, but it might take several weeks to a few months.  A bait that is too strong will kill the ants before they make it home, and a bait that's too weak will only weaken the colony temporarily, so here are some recipes that people have had success with:

  • 1 cup water, 2 cups sugar, 2 tablespoons boric acid
  • 3 cups of water with 1 cup of sugar and 4 teaspoons of boric acid. Remove any deterrents (from previous steps) and wait for the ants to show up. Don't lure new ants with the bait; you could attract new colonies. Once there's a trail, place the bait next to it (not on it, or else you'll interrupt their march home).If you have pets and/or children around (see Warnings below) put the bait in a jam jar. Screw the lid tightly and seal with adhesive tape. Pierce two or three small holes in the lid, and smear the outside with a little bit of un-poisoned bait. If you're concerned about the jar getting knocked over and the poisoned bait spilling out, loosely pack the inside with cotton balls. Just to cover all the bases, leave out some peanut butter bait as well (peanut butter mixed with Borax or boric acid powder). Ants' cravings vary depending on the needs of the colony. Sometimes they want sweets, sometimes they want something oily, so providing both will increase the likelihood that they'll take the bait. Give them as much fresh bait as they'll take, replenishing it as needed, and let them bring it back to their nest (no squishing or killing!). Once they've had their fill, remove all bait; you don't want to attract a neighbouring colony. A solution for getting rid of ants is easy to make! All you need is rubbing alcohol (no alcohol drinks!) dish soap and water. Get a spray bottle, making sure to wash it out very well, and place about a teaspoon of rubbing alcohol, and about a teaspoon and a half of dish soap. Then fill the spray bottle with water, about an inch away from the top, and close it up tight. Shake the solution until bubbles start to appear and then you're ready to spray! The solution is okay to use around children, just wipe up the mess. And because of the alcohol in the solution, the ants will stay clear away from it. So spray the openings of where the ants appear to be coming and going. The solution kills all bugs on contact, so you can even use it on plants! But if you do, make sure to spray the plant only twice! No matter how big or small it is; it'll keep away any ants, but other bugs might not seem affected by it.6If you have ants that apparently come from nowhere, your last resort may be a "Deep Reach" fumigator (aka "fogger"). These are reported to kill ants for 6 to 8 months, with the downside being that you may have to stay out of the place you fumigate for anywhere from a few hours, to a few days, depending on the fumigator. Search online for product reviews, and inquire at local home improvement stores. Make sure you know the volume of the place you need to fumigate.

Attribute Description

  • Caste Monogyn
  • Queen phenotype 7 - 9 mm long, colour black
  • Worker phenotype 3 mm to 5 mm long, colour dark brown almost black
  • Soldier phenotype N/A
  • Nest building Nests underground, commonly found under stones, but also in rotten deadwood
  • Nutrition Nectar, small insects, seeds, will farm aphids for food
  • Lasius Niger colonies can reach in size up to around 15,000 workers but 4,000–7,000 is around average. A Lasius Niger queen can live for around 12 years.


Mating flights ants mate on the wing, so "flying ants" may be males or immature queens. Mating / nuptial flights of Lasius Niger usually occur around June to September throughout the species' range; in North America flights usually occur during the autumn, whereas in Europe they generally take place during the hot summer months of July and August. Flights can contain thousands of winged males and females.

Disparities between local weather conditions can cause nuptial flights to be out of phase amongst widespread populations of L. Niger. During long-lasting, hot summers, flights can take place simultaneously across the country, but overcast weather with local patches of sunshine results in a far less synchronised emergence of Alates (winged individuals).

Once the queens have mated they will land and discard their wings and begin to find a suitable place to dig a tunnel. Meanwhile the males generally only live for a day or two after the mating flights and will then die. Queens live longer than males.

New Nest

Once the tunnel has been completed a queen will block the entrance and retreat to the bottom. Subsequently the queen will begin to dig out a small chamber, this will serve as the founding chamber of the new colony. Generally a queen will begin to lay eggs immediately after the construction of the chamber, the eggs will hatch after 8-10 weeks. Until the eggs hatch and grow to maturity a Lasius Niger queen will not eat relying on the protein of her wing muscles to be broken down and digested. In some cases a Lasius Niger queen may eat her own eggs in order to survive.


Egg to Ant

Lasius Niger have 4 stages of development egg, larva, cocoon and adult. Lasius Niger lay tiny, white kidney shaped eggs with a smooth sticky surface which helps them to be carried in a group instead of one by one. After hatching Lasius Niger proceed onto the larva stage resembling tiny maggots. The larva need to be fed by the queen (or workers in the case of an established colony) if they are to mature, as they feed the larva grow shedding their skin, doing so usually three times in total. With each moult the larva grow hooked hairs which allows them to be carried in groups. When Lasius Niger larva reach the last moult they are generally too big to be carried as part of a group and so are carried singularly. Once the larva grows big enough it spins a cocoon around itself. To aid this process a queen (or workers) may bury the larva so that it can spin its cocoon undisturbed, and begins a process of metamorphosis. Once the process is complete the Lasius Niger worker emerges from the cocoon, at this stage Lasius Niger is completely white but will darken over the course of an hour until it has turned black.

Colony Established

The first workers that emerge are very small compared to later generations. At this point the workers immediately begin to expand the nest and care for the queen and brood, they eventually remove the seal from the entrance to the nest and begin to forage above ground. This is a crucial time for the colony as they need to gather food quickly to support future growth and particularly to feed the starved queen, who would have lost around 50% of her body weight. From this point on the queen's egg laying output will increase significantly, becoming the queen's sole function. The later generations of worker ants will be bigger, stronger and more aggressive, reason being dependent on the amount of nutrition Lasius Niger receives at the larva stage. The initial brood being fed only by the scarce resources available to a queen will be much smaller than brood supported by a team of foraging and nursing workers. Provided workers are able to find food at this stage the colony will see an exponential rise in population. After several years once the colony is well established the queen will lay eggs that will become queens and males. Black ants often make large nests with extensive tunnel connections.

 As a Pest in the Garden

This type of ant is a problem for some gardeners. They will farm aphids for the honeydew they excrete by bringing them inside the nest and bringing them back out again when necessary. The ants will also eat ripe fruits, especially fruits like strawberries that lack a thick protective skin. Often they can be found on discarded chewing gum. Lasius Niger also feed on insects and spiders, and other small invertebrates. In Ireland they are usually referred to as pismires, an archaic term for an ant.

In the home

Black garden ants often explore their surroundings quite extensively during early summer months in an effort to increase the food supply to their queen and her young, and also as a way of testing new ground in preparation for the nests' summer flight. In some cases, these explorations lead to a burrowing through mortar and brick.

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